HPCC-9428 Remove @ sign from Deleting File confirmation

A @ sign after a filename is used to pass cluster information to
Delete Logical File function. But. the @ sign should not be shown
inside the confirmation message for deleting the file. This fix
removes the @ sign from the confirmation message.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>
Merge pull request #4496 from wangkx/h9428

HPCC-9428 Remove @ sign from Deleting File confirmation

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>